This invention relates to the fabrication of parts and devices and more particularly to a part-making assembly that uses energetic ions to melt feedstock and selectively apply it to the workpiece.
The manufacture of parts, prototypes, and the like is an important component to industrial processes, because the manufacture of parts leads to the manufacture of machines which can make useful devices on commercial and industrial levels. Additionally, specialized machines such as jet engines and the like require special parts that must generally be manufactured by hand to a high degree of precision. Consequently, the manufacture of parts and tools are an important part of commercial and industrial activity.
One means by which parts can be made is to take a block of material and cut away the unnecessary portions to leave the part in question. Lathes and the like act in this manner and may use aluminum, steel, or wood as materials from which parts can be made. Saws, routers and the like serve in much the same way.
Recently, it has become possible to manufacture parts from scratch as by stereolithography or laser sintering. In some embodiments, stereolithography uses optical or other focused radiation in order to bind or transform a liquid into a solid in a manner that is consistent with a desired piece or portion in a planar manner. The surface of the liquid melt is bombarded with focused radiation, which causes a solid to form. The radiation is altered or redirected according to the cross-section necessary, relevant, and as associated with a prior cross-section fabrication. In this manner, thin cross-section pieces are constructed in a coordinated manner to ultimately achieve the final workpiece or part. The stereolithographed part can then be used to make a mold from which actual parts can be cast from preferred materials (such as steel, aluminum, or the like). Laser sintering uses a powder subject to the energetic bombardment of laser energy. In much the same way as stereolithography, certain pieces or parts of a structure can be formed in an on-going manner. By careful application and addition of the laser-sintering process, parts can be formed.
Chemical vapor deposition also provides a means by which thin layers can be applied to a workpiece in order to build it up. Chemical vapor deposition, or CVD, is often used in the fabrication of monolithic micro-circuitry.
Additional devices and apparatus exist that apply material to a workpiece in a gradual fashion in order to form the ultimate part or device. While these devices are generally acceptable, each has drawbacks according to the particular technologies used to achieve the fabricating systems. For example, stereolithography can be very expensive and is not necessarily the most effective way to make a part as an actual workpiece is not formed as material such as steel, aluminum or the like are not amenable to stereolithographic processes. Instead, a special melt substance must be used in order to form the workpiece positive from which the mold-negative can be formed. With respect to laser sintering and the like, powder is used that can become an obstacle in the easy fabrication of parts and the like. With CVD, the deposition process generally takes place in a low pressure or vacuum atmosphere. This requires additional equipment in order to provide such a low density atmosphere, increasing costs and maintenance requirements.
Certain patents have issued, including the following: U.S. Pat. No. 4,323,756 issued to Brown et al. on Apr. 6, 1982 for a Method for Fabricating Articles by Sequential Layer Deposition; U.S. Pat. No. 4,411,733 issued to Macklin et al. on Oct. 25, 1983 for a SPER Device for Material Working; U.S. Pat. No. 5,837,960 issued to Lewis et al. on Nov. 17, 1998 for Laser Production of Articles from Powders; and U.S. Pat. No. 6,046,426 issued to Jeantette et al. on Apr. 4, 2000 for a Method and System for Producing Complex-Shape Objects assigned to Sandia Corporation.
The Brown et al. ""756 patent describes the fabrication of symmetrical objects by laser or electron beam. This patent does not mention the use of plasma for part construction, and does not address the construction of non-symmetrical devices. The Macklin et al. ""733 patent describes a device having an enclosing chamber used to deposit the vaporized-electrode plasma itself, and not a feeded-construction material onto the target. Deposition rates for a Macklin-like device may be low.
In the device shown in the Lewis et al. ""960 patent, a laser is used to melt powdered particulate at a deposition point and thereby produce articles. No plasma torch is described, nor is a feed mechanism for a plasma torch. In the Jeantette et al. ""426 patent, an object-producing apparatus uses powdered material to effect the manufacturing process. A laser beam fuses the powdered material to the object under construction to obtain near-net- or net-shape objects. No use of a plasma torch is described, nor is use of non-powdered materials. Such laser-reliant systems generally do not provide a large melt pool for faster deposition yet also provide for smaller melt pools for tighter tolerances. Such laser systems generally do not provide a wide range of almost-instantly available power, a wide range of wire speeds, and the ability of the associated positioning device to rotate the workpiece into the horizontal position. Losses also occur at light-transmission junctions such as those present with associated fiber optics.
Many of the features seen in the Jeantette et al. ""426 patent and the Lewis et al. ""960 patent are also seen in U.S. Pat. No. 6,203,861 issued to Kar et al. on Mar. 20, 2001 for One-Step Rapid manufacturing of Metal and Composite Parts. However, the Kar et al. ""861 patent describes the use of multiple beams for multiple processing.
It would be of significant advantage to provide means by which part and pieces could be fabricated in a manner that is advantageous to manufacturers while using readily available and understood technology in a useful and familiar manner.
Ion Fusion Formation (IFF) is a mechanism that fabricates components without machining, molds, or mandrels. In most conventional component fabrication, a block of material is machined to shape and size, or a mold is used as in castings or material is deposited on a mandrel as in chemical vapor deposition. IFF builds a part by applying small amounts of molten material only where needed to build a part. The components are formed in many small deposition steps resulting in net-shape or near-net-shape parts. Any fusible material, metal, ceramics, plastics, etc. or combinations can be used to build parts with this process.
The key components of the device are a concentrated ion heat source, a material conveyance system, and a positioning system. Additional components required are electrical power and a controller and/or computer with a positioning system. Small amounts of material are placed on top of a base or previous deposition point. The ion heat source can be composed of positive ions, negative ions, combinations thereof, electrons solely, or ions of any sort in combination electrons. The ion heat source must be concentrated to some extent in order to enable building in small increments. Concentration can be accomplished mechanically with orifices of varying sizes or electromagnetically. The smaller the increments of material deposited, the more accurate is the building system. However, for larger components, ion sources with larger cross-sectional areas, and more heat, could be used to deposit larger amounts of material per deposition point. Small and large ion heat sources could be used together to give high deposition rates in some areas of the component and high accuracy in other areas.
Material for deposition can be conveyed to the point of fusion by a feedstock feeder (including powder feeders and wire feeders) or any other feedstock transport mechanism. Preferably, the feeder should be able to vary material transport rate to optimize deposition speed with heat input.
The building scheme for a specific part may typically based on an electronic model (such as a CAD-CAM file), but build instructions could be programmed into the controller manually. While computer control is preferred for most of the more complex components, simple forms, such as tubes and cylinders, could be created without the computer and by only using the positioner controller. A preferred approach, but not the only approach, is to use existing CNC (Computer Numerical Control) programming language to control the positioner. However any control language with software capable of representing 3 dimensional entities such as STL (Stereolithography Language) is acceptable.
A preferred deposition approach for many components, but not the only approach, is layer building. Horizontal slices are taken through the three dimensional electronic model by computer programs. The positioner then deposits material across each layer at a prescribed thickness. The controlling instructions will position the deposition at the appropriate point on the component and will also not deposit material at holes or other voids.
Movement of the hardware to its appropriate location can be accomplished by X-Y-Z, vertical and rotational motion. Alternatively, the ion heat source can be moved in like manner or the part and ion source can be moved simultaneously or alternately.
In summary, ion fusion formation (IFF) can be used to eliminate many steps which currently exist in fabrication processes. By reducing machining and molding steps, products can be brought to market faster, manufacturing or other schedules can be met on time, and components that have been incorrectly processed in non-machine phases can be quickly replaced. In short, IFF may provide the potential to deliver xe2x80x9cinstant partsxe2x80x9d, and xe2x80x9cjust-in-timexe2x80x9d manufacturing becomes even more possible than ever before.
Other features and advantages of the present invention will become apparent from the following description of the preferred embodiment(s), taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.